I have to agree with Ignition Override here. Having seen 3 jet pipe fires, there is no need to evacuate. Just signal (figure 8 as described) or tell the crew via the headset of the fire and get them to dry motor the engine to put out the fire! There is even enoughtime to relocate towards the rear of the a/c (suitably clear from any jet blast of course) so you can observe and inform the crew if the fire has extinguished. If it wont go out there are 2 options.
1. Get the fire crews to put CO2 into the jet pipe (NOT water or foam the thermal shock could be very expensive) Powder/chemicals should not be used as there can be a reaction with the blade alloys (also expensive).
2. Light her up!!
older low bypass engines may not have enough puff to blow out the fire. I have seen this once on a 707/JT3. It was impressive as 20ft flames shot out of the jet pipe, but it worked.